This study considers automatic scallop harvesting using the drone with the robot arm as the new scallop fishery. The fishery needs the dedicated gripper attaching the robot arm. This study judges the adsorption gripper as the dedicated gripper. The adsorption gripper must push itself to the object during gripping motion. If the pushing force is too large, there are some problems with the grasping. This study focuses on the flexibility of the gripper tip contacting object to solve those problems. Then, we investigate the applicability considering on the relationship between shape and flexibility of the adsorption gripper tip from the experiment. From these considerations, the dedicated gripper has been developed.